Okay, to use Vortec Heads you need the sdpc Vortec TPI base, right? Well, then what Vortec Head do you get? I didn't see any for TPI, only for TBI. Does it matter? And are they for off-road use only or what?

Or an even better question, are there better heads that I can get without having to get a special TPI base/manifold?

 

Vortec heads are vortec heads, any you buy will work. However there are different casts, some better then others. I've asked the same questions and alot of people say that Pro Action Lightning heads flow very well at a very good price. Do a search for Pro and Lightning